A leading member of Spain's ruling Popular Party (PP), Cristina Cifuentes, has resigned as president of the Madrid region after a scandal over her allegedly fraudulent master's degree was compounded by revelations she had been arrested for shoplifting.

A leading member of Spain's ruling Popular Party (PP), Cristina Cifuentes, has resigned as president of the Madrid region after a scandal over her allegedly fraudulent master's degree was compounded by revelations she had been arrested for shoplifting.

Ms Cifuentes, tipped by many as a potential successor to Spanish Prime Minister Mariano Rajoy as leader of the PP, had stubbornly refused to resign even as a judicial investigation was launched into her master's degree in public law from the King Juan Carlos University in Madrid.

But she buckled after a video was published yesterday morning appearing to show her being stopped by supermarket security guards for taking anti-ageing cream without paying.

Her fate was sealed as the once centrist party Ciudadanos stated that it would support a motion of no confidence in the regional parliament - meaning that the PP would lose power in a region it has governed since 1995 - unless Ms Cifuentes stepped down.

"I have held on for more than 34 to 35 days of permanent exposure. What has happened today crosses a line," Ms Cifuentes said in reference to the fresh allegations as she resigned in front of the cameras.

Yesterday morning, the online newspaper 'OK Diario' reported that the politician had been arrested by supermarket security guards in 2011 on suspicion of having shoplifted two pots of anti-ageing cream.

A video that was published with the story showed Ms Cifuentes emptying her handbags in front of a guard in a store backroom.

"It was an involuntary mistake," Ms Cifuentes claimed afterwards.

"Without realising, I took two products worth 40 euro, they told me about it and I paid up.

"That recording has been used to go beyond politics," Ms Cifuentes said, adding that she had previously been the victim of attempted extortion owing to the tape.

"I don't want to hurt my family, for whom I am taking this decision so that they don't carry on suffering this Calvary.

"It's the best thing for Madrid's citizens and for my party."

Mr Rajoy told reporters in Congress that Ms Cifuentes had "done what she had to do" and "opened up a new era for the PP in Madrid".

Ms Cifuentes hinted that she has been unfairly treated during coverage of the two scandals, and appeared to draw a line between her pledges to tackle corruption and attacks from her opponents.